THe Delta is a nifty high speed design, but terrible for low speed control ( speed unstable ) hence the need for an extra human on the COncorde flight deck to work the throttles - in case the analog autothrottles gave up.. We also saw an example of the delta low speed performace with the last fateful Concorde accident. Boeing recognised this commercially unacceptable penalty & went with the swing-wing on the SST baseline configuration which ended up on the the B-1 & F-111 bombers. But AirFOrce experiance was that a redundant autopilot weighed alot less than the clap trap & hugh swingwing bearing & led the Boeing sonic cruiser back to the delta configuration.. Boeing developed an integrated autothrottle - autopilot suite called "total-energy" that allowed pilots to fly in the "behind the power curve" speed unstable regime with docile speed stable - conventional characteristics .. Space Shuttle is also delta ..